U.S. patent number 4,419,992 [Application Number 06/233,725] was granted by the patent office on 1983-12-13 for occlusal splints and the method of manufacturing the same.
Invention is credited to Peter M. Chorbajian.
United States Patent |
4,419,992 |
Chorbajian |
December 13, 1983 |
Occlusal splints and the method of manufacturing the same
Abstract
Disclosed are occlusal splints and the method of manufacturing
the same. The occlusal splints described are worn on the upper arch
of the mouth over the teeth. They are formed of two layers. The
first layer is formed of a soft material molded to conform to the
shape of the upper teeth and to be resiliently retained thereon,
and the second layer is made of cold-cure acrylic resin built up on
the first layer.
Inventors: |
Chorbajian; Peter M. (Bethesda,
MD) |
Family
ID: |
22878445 |
Appl.
No.: |
06/233,725 |
Filed: |
February 12, 1981 |
Current U.S.
Class: |
128/862;
433/6 |
Current CPC
Class: |
A63B
71/085 (20130101); A61C 7/08 (20130101) |
Current International
Class: |
A61C
7/08 (20060101); A61C 7/00 (20060101); A63B
71/08 (20060101); A61F 005/56 () |
Field of
Search: |
;433/215,6,229
;128/136 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Verschoth, Sink Your Teeth Into This. .
Guichet, The "Nightly Grind," Family Health (Jun. 1970)..
|
Primary Examiner: Peshock; Robert
Attorney, Agent or Firm: Byrne; John J.
Claims
What is claimed is:
1. An occlusal splint sized and shaped to be worn on the upper arch
of the mouth over the teeth, said occlusal splint being formed of
two layers of resin, the upper layer molded to conform to the shape
of the upper teeth and to be resiliently retained thereon, and a
lower layer formed of a cold-cure resin built up on the upper
layer, the lower surface of said lower layer shaped so that when
the lower jaw is moved toward the upper arch with the condyls of
the wearer in their retruded rest position the upper surfaces of
the lower teeth will engage said lower surface of the splint at the
same time and said areas of engagement of those teeth that are in
engagement are all below the plane of the lowermost edges of said
upper teeth.
2. An occlusal splint as recited in claim 1 wherein said upper
layer is formed of acrylic resin.
3. An occlusal splint as recited in claim 1 wherein said upper
layer is formed of a resilient mouthguard material.
4. An occlusal splint as recited in claim 3 wherein said upper
layer extends above the greatest curvature of at least some of the
upper teeth.
5. An occlusal splint as recited in claim 1 wherein:
(a) the upper portion of the splint is formed of a resilient
material and
(b) the upper portion of the splint extends above the greatest
curvature of at least some of the upper teeth,
whereby the splint is resiliently retained on the upper teeth.
Description
TECHNICAL FIELD
This invention relates to occlusal splints and to methods of
manufacturing occlusal splints.
BACKGROUND OF THE PRIOR ART
Some occlusal splints are used as diagnostic and repositioning
tools. They are worn until the patient has had a proper occlusal
diagnosis and evaluation after a clinical examination of the
complete gnathostomatic system before a permanent (and
irreversible) program is undertaken to change the occlusion. In
this capacity, occlusal splints serve as a reversible procedure to
confirm an occlusal diagnosis and to temporarily relieve the
symptoms of malocclusion and tempromandibular joint
dysfunction.
Other occlusal splints are used to relieve strain and tension,
particularly in athletes. Such splints are typically formed from a
sheet of resin which is shaped to follow the surface of the teeth.
Thus, the distal surface of the splint has a shape which closely
approximates the shape of the teeth over which the splint is
worn.
Still other occlusal splints are worn simply as cushioning. Such
splints are also commonly worn by athletes, particularly athletes
involved in contact sports, such as football and boxing, and they
are made of a soft, "chewy" material known as "mouthguard
material."
BRIEF SUMMARY OF THE INVENTION
The occlusal splint according to this invention has an outside
surface (i.e., the surface which contacts the lower teeth) formed
of a relatively hard, non-resilient material which is shaped so
that all the lower posterior teeth strike the splint at the same
time, equalizing the pressure on each lower posterior tooth. The
upper portion of the splint (i.e., the portion next to the teeth
and palate) is formed of a resilient material which extends above
the greatest curvature of at least some of the upper teeth,
permitting the splint to be retained resiliently on the upper teeth
by a "snap fit."
ADVANTAGES OF THE INVENTION
An occlusal splint according to this invention measures the degree
of closure and allows the brain to reprogram the mandible to any
position of closure that will be completely acceptable and will
afford maximum comfort without straining or stressing the
musculature of the gnathostomatic system. It does not add power,
but it does release strength which the wearer already has but which
is tied up by stress due to the wearer's teeth not being properly
aligned.
One may have tempro-mandibular joint dysfunction without being
aware of it. Such dysfunction, when due to a lack of balance
between the upper and lower teeth, exhausts muscle strength by loss
of tonus, causing fatigue and pain. Soon other muscles are used to
perform the function of muscles that are already exhausted. As a
result, there is a general strain of all of the musculature.
However, an occlusal splint according to this invention
substantially alleviates, and sometimes eliminates,
tempro-mandibular joint dysfunction.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view looking upwardly towards a first
embodiment of an occlusal splint according to this invention in
position on the upper teeth or on a mold of the upper teeth. The
occlusal splint is shown in broken line in order to clearly show
its relationship to the teeth.
FIG. 2 is a cross-sectional view on a larger scale along the line
2--2 in FIG. 1.
FIG. 3 is a top plan view of the occlusal splint shown in FIG.
1.
FIG. 4 is a bottom plan view of the occlusal splint shown in FIG.
1.
FIG. 5 is a cross-sectional view along the line 5--5 in FIG. 3.
FIG. 6 is a side view of the occlusal splint in position on the
upper teeth or on a mold of the upper teeth.
FIG. 7 is a view similar to FIG. 2 of a second embodiment of an
occlusal splint according to this invention.
FIG. 8 is a top plan view of the occlusal splint shown in FIG.
7.
FIG. 9 is a view along the line 9--9 shown in FIG. 8.
FIG. 10 is a side view of the occlusal splint shown in FIG. 8 in
position on the upper teeth or on a mold of the upper teeth.
FIG. 11 is a bottom plan view of the occlusal splint shown in FIG.
7.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
The occlusal splint 10 shown in FIGS. 1-6 is adapted to be worn on
the upper arch of the mouth over the upper teeth 12 substantially
twenty-four hours a day--that is, at all times except when the
patient is eating. As best seen in FIGS. 2 and 5, it extends
upwardly to the palate gums 14 on the lingual (or inside) surface
16 of the teeth 12, but does not do so on the labial (or outside)
surface 18 of at least the anterior, or front, teeth. However, the
fact that the splint does not extend as far up towards the gums 14
on the labial surface 18 is for cosmetic rather than functional
reasons, and the splint can extend upwardly to the gums 14 on the
palatal/lingual surface. In any event, as shown in FIG. 1, the
splint 10 extends above the greatest curvature of at least some of
the upper teeth 12 (namely, the pre-molars and molars) on both
sides.
The splint 10 is formed of two layers of resin, preferably acrylic
resin. The first, or inside, layer 20 is molded to conform to the
shape of the upper teeth. It is made from an acrylic resin sheet of
uniform thickness, so the lower surface of the upper layer 20
closely approximates the shape of the teeth over which the splint
is worn, as is the case with conventional splints. However, the
second, or outside, layer 22 represents a radical departure from
conventional splints. The outside layer 22 is made of cold-cure
acrylic resin built up on the first layer 20. As is explained in
detail hereinafter, the outside surface of the outside layer 22 is
shaped so that all the lower posterior teeth strike the splint at
the same time, equalizing the pressure on each lower posterior
tooth. As seen by the diagrammatic lower surfaces in FIGS. 6 and
10. Since the upper portion of the splint 10 is formed of a
resilient material, the splint is retained resiliently on the upper
teeth by a "snap fit."
The first step in preparing on occlusal splint according to this
invention is to make a model of the upper arch by conventional
techniques. The model is sprayed with an even coat of silicone mold
release--preferably Crown 2 silicone mold release. Care is
exercised in this step, since over-spraying causes undesirable side
affects in the finished splints and underspraying causes sticking
between the model and the splint.
Next, a moldable resin splint blank (preferably formed of acrylic
resin 0.080 or 0.100 inches thick) is heated until it becomes
pliable. While the splint blank is pliable from the heat, it is
formed to the model. This is done in a Microform press using 90
lbs./sq. in. pressure.
The splint blank is allowed to cool. It is then cut on the buccal
surface slightly above the greatest curvature of the bicuspid and
molar teeth and approximately `mm above the incisal edge of the
anterior teeth. The cut extends in a continuous, smooth line form
the distal surface of the most posterior molar on one side to the
distal surface of the most posterior molar on the other side. This
can be accomplished, for example, using a #703 long shank burr in a
straight low-speed handpiece. No portion of the palatal area is
removed at this time.
After cutting, the splint blank is removed from the model by prying
at the posterior border, thereby removing the formed splint blank
in an anterior direction. A beaver-tailed wax instrument may be
used as a lever. The reason for removing the splint blank from the
model back to front, rather than vice-versa, is to avoid the
fracturing of teeth on the model and, more importantly, to avoid
distortion of the splint blank at it is removed from the model.
The uppermost palatal area of the splint blank is then removed
behind a line connecting a point lingually spaced from the cervical
line of the most posterior tooth on one side, a point lingually
approximately 15 mm from the cervical line of the anterior teeth,
and a point lingually spaced from the cervical line of the most
posterior tooth on the other side. This is accomplished by drawing
a continuous, smooth line connecting these three points using an
indelible pencil and then cutting away the splint blank outside the
line using a #703 long shank burr in a straight low-speed
handpiece.
Next, the margin of the splint blank is made smooth, as with an
acrylic burr, and a trial fit of the splint blank in the patient's
mouth is made to check for irregularities. The splint blank is then
removed from the patient's mouth, and the lingual surface over all
the teeth and the occlusal surface over the biscuspid and molar
teeth are scarified to promote adherence thereto of the cold-cure
resin which is built up thereon in subsequent steps. The
scarification may be done with a long shank green stone.
At this point the patient's mandible is exercised manually and
closed against the upper jaw in a manner so that the condyle on
each side is in the most retruded rest position of the glenoid
fossa of the temporal bone on each side, which is termed to be a
centric relation. The patient is asked to bite on two cotton rolls
anteriorly to maintain the relation of the lower jaw to the upper
jaw.
The cotton rolls are then removed, the patient's lower anterior
teeth are lubricated with a thin film of petroleum jelly, and the
anterior portion of the scarified splint blank is wetted with a
liquid component of a cold-cure resin (preferably cold-cure acrylic
resin). A portion of dough-like cold-cure resin then is placed on
the rugae area of the splint blank behind the anterior teeth and
flattened over the anterior portion of the splint blank to the
contour of the anterior palate, and the formed splint blank is
placed on the patient's upper teeth. While the cold-cure resin is
still pliable, the mandible is closed in centric relation. The
patient at this time is guided to closure until a slight contact is
made between his or her anterior lower teeth 24 and an apron 26 of
the previously emplaced soft, pliable resin behind the upper
anterior teeth 18 (see FIG. 2). This slight contact leaves an
impression of the anterior teeth called an index in the resin.
During this step care is exercised to ensure that a clearance of at
least approximately 2 mm is maintained between the formed splint
blank over the most posterior area of the upper molar teeth and the
corresponding most posterior area of the lower molar teeth.
Next, after the cold-cure resin has begun to harden but before it
becomes painfully hot due to the exothermic reaction between the
acrylic monomer and the acrylic polymer, the assembly comprising
the splint blank and the build-up resin on the anterior portion of
the splint blank is removed from the patient's mouth. Two cotton
rolls placed over each other are again inserted between the
anterior teeth to prevent the patient from moving the condyles out
of the most retruded rest positions of the glenoid fossae of the
temporal bones, and the patient is asked to close in a natural
bite--not an edge-to-edge closing. After the cold-cure resin has
hardened, it is reduced to the deepest depth of the impressed
index, until only one lower anterior tooth contacts only one point
on the indexed surface. The remainder of the newly hardened
cold-cure resin is shaped to the form of the palate, providing room
for the patient's tongue. This is accomplished using an acrylic
burr.
The cotton rolls are then removed from the patient's mouth, and the
splint is re-positioned on the upper teeth. The patient is asked to
hold marking ribbon between the splint and his or her lower teeth,
and the mandible is moved from centric relation to a forward
position, then back, then to one side, back, then to the other
side, and back. These movements are repeated several times before
the splint is removed. After the splint is removed, fresh cotton
rolls are again inserted between the patient's anterior teeth to
prevent him or her from moving his or her condyles out of the most
retruded rest position of the glenoid fossae of the temporal bones,
and the patient is asked to close his or her teeth in a natural
bite as before.
Any eccentric marks found on the hardened cold-cure acrylic are
removed at this time. The only point of contact is made now by only
that single lower anterior tooth with the jig of the splint at one
point only. This procedure permits the jaw muscles to be
reprogrammed so that the mandible attains a natural centric
relation because the lower teeth slide across the smooth lower
surface of the splint until the lower tooth which made the deepest
index comes to rest against the remaining portion of that index,
which has previously been established as defining the centric
relation.
The splint is then removed, and the patient's lower posterior teeth
(i.e., his or her bicuspid and molar teeth) are lubricated with a
thin film of petroleum jelly. Cotton rolls are again placed between
the anterior teeth. The bicuspid and molar areas of the scarified
splint blank are wetted with a liquid component of a cold-cure
resin (preferably, the same cold-cure acrylic resin), after which
portions of dough-like cold-cure resin are placed over the wetted
bicuspid and molar areas on both sides of the splint blank. The
cotton rolls are then removed from between the patient's teeth, and
the formed splint blank is placed on the patient's upper teeth.
While the cold-cure resin is still pliable, the mandible is again
positioned in closed centric relation, the centric relation now
being determined by contact between the lower anterior tooth which
made the deepest depression in the cold-cure resin previously
emplaced and the remaining portion of that index. The contact
between the posterior lower teeth and the soft, pliable resin over
the posterior upper teeth leaves indices in the resin, as
before.
After the cold-cure resin has begun to harden but before it becomes
painfully hot due to the exothermic reaction between the acrylic
monomer and the acrylic polymer, the assembly comprising the splint
blank, the hardened cold-cure resin on the anterior portion of the
splint blank, and the still pliable cold-cure resin on the
posterior portion of the splint blank is removed from the patient's
mouth. Two fresh cotton rolls are inserted between his or her
anterior teeth to prevent him or her from moving his or her
condyles out of the most retruded rest position of the glenoid
fossae, and the patient is asked to close his or her teeth in a
natural bite as before.
After the cold-cure resin on the posterior portion of the splint
blank has hardened, the indices in the posterior portion of the
splint blank are marked. This may be done using black Liqua Mark
marking fluid which is dried after application with an air syringe.
The resin surrounding the indices made in the posterior portion of
the splint by the posterior lower teeth is then removed until only
small dots on the order of 0.05 mm. in diameter remain where the
cusp tips of the bicuspids and molars made the deepest depressions
in the pliable resin. It should be particularly noted that, in
contrast to the comparable step involving the indices made by the
lower anterior teeth, the deepest portions of the indices made by
the cusp tips of all of the lower posterior teeth are allowed to
remain in the splint. This step is also accomplished with an
acrylic burr.
Any excess hardened cold-cure resin is then removed from the
lingual, buccal, and occlusal surfaces of the splint, taking care,
of course, to leave the previously mentioned single index for one
of the lower anterior teeth and the multiple indices of the lower
posterior teeth. This step, too, is accomplished using an acrylic
burr.
Next, the hardened cold-cure resin extending back over the palate
is trimmed away, since it is no longer needed for ease of handling,
leaving the splint in a shape resembling a horseshoe. This is
accomplished using a #703 long shank burr in a straight low-speed
handpiece.
Eccentric contacts (i.e., places where the lower teeth would bump
into the splint when the mandible is moved from side to side) in
the anterior lingual area are then removed to develop the lingual
concavity. This step is also accomplished using a #703 long shank
burr in a straight low-speed handpiece.
Next, the exterior surface of the splint is smoothed, for instance
with the use of an acrylic burr, while carefully preserving the
remaining 0.5 mm. portions of the indices in the splint.
Finally, the exterior surfaces of the occlusal splint are finished,
for instance with pumice and Final Lustre finishing compound, and
the finished splint is positioned in the patient's mouth.
It should be noted that occlusal splints made by the foregoing
process, like all occlusal splints, can be worn only for a
restricted period of time before they lose their efficacy due to
wear of the surfaces which contact the lower teeth. They should be
worn only until the patient has had a proper occlusal diagnosis and
evaluation after a clinical examination of the complete
gnathostomatic system. After such a complete occlusal diagnosis and
evaluation has been accomplished, a permanent, irreversible program
can be undertaken to change the patient's occlusion.
Occlusal splints made by the foregoing process may be used (1) as a
diagnostic and repositioning tool and (2) as a temporary
strain-reliever for patients in high tension situations. In the
former situation, use of the splint serves as a reversible
procedure to confirm an occlusal diagnosis and to temporarily
relieve the symptoms of malocclusion and tempro-mandibular joint
dysfunction. In the latter situation, while individual splints will
lose their efficacy due to wear, replacement splints can be made
and the use of such splints continued indefinitely.
Second Embodiment
The occlusal splint 40 shown in FIGS. 7-11 is similar to the
occlusal splint 10 shown in FIGS. 1-6 except that it is
specifically adapted to be worn in situations where forceful
contact (as from body-contact sports) is anticipated by the wearer.
Thus, this occlusal splint is not ordinarily worn twenty-four hours
per day, as is the first embodiment. The second embodiment is also
adapted to be worn on the upper arch of the mouth over the upper
teeth 12, and it is also formed of two layers. However, the first,
or upper, layer 42 is preferably formed of polyurethane mouthguard
material rather than acrylic resin. It is also molded to conform to
the shape of the upper teeth 12 and to be resiliently retained
thereon, but, as best seen in FIGS. 7 and 9, it extends upwardly to
the gums 14 on both the lingual surface 16 and the buccal surface
18 of at least the front teeth. Thus, the splint 40 also extends
above the greatest curvature of at least some (and preferably all)
of the upper teeth 12, and, since the upper portion of the splint
40 is also formed of a resilient material, the splint 40 is also
retained resiliently on the upper teeth 12 by a "snap fit."
The second embodiment can be made by the same technique as the
first embodiment except (1) a blank made of 0.150 or 0.200 rubber
or a similar mouthguard material is substituted for the thinner
blank of acrylic resin, (2) the molded splint blank is removed from
the model of the upper arch by reversing it, rather than by prying
if off, since it is considerably more resilient than the molded
acrylic splint blank, (3) the trimming steps can be accomplished
using small scissors rather than a #703 long shank burr, since the
mouthguard material is easier to cut than the acrylic resin, and
(4) the posterior palatal area of the splint may or may not be
removed, depending on the patient's tolerance of a foreign body in
contact with the roof of his or her mouth.
Caveat
While the present invention has been illustrated by a detailed
description of two preferred embodiments thereof, it will be
obvious to those skilled in the art that various changes in form
and detail can be made therein without departing from the true
scope of the invention. For that reason, the invention must be
measured by the claims appended hereto and not by the foregoing
preferred embodiments.
* * * * *